On the general Nature of Bolides. 289 



hi their statements on this subject; those discrepancies must 

 have arisen, I conceive, from the circumstance, that the disk 

 of the meteor actually varied in size at different periods of its 

 course ; and variation to such an extent as is indicated by them, 

 in so small a space of time as that occupied by the passage of 

 this fire-ball, could only have taken place in ignited gaseous 

 matter, or flame, proceeding, however, from the combustion 

 of solid matter. 



Such are the grounds on which I have founded the opinion 

 above given of the nature of this meteor; and as the assumption 

 that the magnitude of fire-balls as computed from their distance 

 and apparent diameter, is the actual size of the solid mass they 

 contain, appears to have led to various misconceptions regard- 

 ing them, I shall take this opportunity of submitting, with 

 much deference, a few facts, tending to show that the magni- 

 tude of fire-balls so computed, is in no case that of the sub- 

 stance of the meteors ; but merely of the flames with which 

 they are invested. I am not prepared to assert that this di- 

 stinction has been overlooked by every writer on the subject ; 

 but it is within my knowledge that it has been neglected by 

 many ; and that others, who seem to have had some idea of 

 its existence, have nevertheless derived much less use from it, 

 in their inquiries concerning the origin and theory of such 

 phaenomena, than it appears to be capable of affording. 



Thus Dr. Bowditch, in his excellent account of the meteor 

 that exploded over Weston, in Connecticut, on the 14th of 

 December 1807, after stating that "the least of all the limits 

 of the diameter of the meteor is 491 feet;" proceeds to com- 

 pare, in the following manner, the quantity of matter which 

 that dimension would indicate it to have contained, with the 

 actual weight of the stones that fell from it: "A body of this 

 magnitude," he says, " and of the same specific gravity as the 

 stone that fell at Weston (which weighed about 225 pounds to 

 a cubic foot) would contain a quantity of matter exceeding in 

 weight six millions of tons. If the specific gravity were the 

 same as that of the air at the surface of the Earth, the quantity 

 of matter would exceed txvo thousand lo?is : and if the specific 

 gravity were the same as that of the air at the height of the 

 meteor (which by the usual rule lor barometrical admeasure- 

 ments is about ^th part of that at the surface of the Earth), 

 the quantity of matter would cxccedflfti/ tons. Either of these 

 estimates exceeds by far the weight of the whole mass that fell 

 mar Weston, which, by the accounts published, docs not ap- 

 pear to have been greater than hali-a-ton, and would not form 

 a sphere of two feel diameter of the same specific gravity as 

 tlie stone, as was observed by Professor Day, in his valuable 



Vol. G4. No. 318. Oct. 1824. Oo paper 



